I installed Kubuntu on three Pentium 4 PCs with 256MB of RAM. On the HP compaq dc5000 PC, Kubuntu runs like lightning. On the Gateway "M" series PC, it installed and logged in but was so slow that it was virtually unusable. On the Gateway "E" series PC, it was usable but slow as molasses. I'm assuming the difference is driver support for the different video/ethernet/whatever hardware between the systems. For example, Xandros and SUSE won't finish installing at all on the "M" series PC, presumably for lack of hardware support.

So, assuming the speed issues on the two Gateway machines are caused by poor hardware support in Linux, how might I diagnose which hardware on them is poorly supported by Linux drivers, and where might I look for such drivers?

Thanks for the help!

You may just want a modern amount of ram. Trying to run on anything with just the base 256 is terrible. You'd probably find out the computers are much more usable with 512+ and perhaps a real video card to take the load off the board